The present invention generally relates to adjustable systems for vehicles, and more particularly to a sensor for an adjustable system of a vehicle, such as an electronically adjustable vehicle pedal system of an automobile.
Most vehicles, such as automobiles, include adjustable electrical, mechanical, and electromechanical systems that perform various functions. One such system is an adjustable pedal system for a vehicle, which includes one or more control pedals for the vehicle, such as an accelerator pedal, brake pedal, and/or a clutch pedal. In recent years, adjustable pedal systems have gained considerable market acceptance, particularly in the automotive industry. Adjustable pedal systems provide mechanisms and controls for adjusting the position of the control pedals in relation to the driver""s position within the vehicle. The relative height of the control pedals can therefore be adjusted to accommodate multiple drivers each having differing anatomic dimensions and relative body proportions.
Presently known vehicle pedal adjusting mechanisms typically utilize a single motor operatively connected to two control pedals via two separate adjustment mechanisms. One of the pedals is typically connected to the motor via a worm gear train or other gear mechanism and the other pedal is typically connected to the motor via a flexible cable. While this type of system provides relative adjustment between the two pedals, it does not provide a sensor for monitoring the relative positions of the two pedals. In the event of a mechanical failure of only one of the two mechanisms, a serious safety hazard would be created if the driver were to adjust the pedal having the properly functioning mechanism substantially out of position with respect to the pedal having the defective mechanism.
Provisional patent application Ser. No. 60/164,434, filed on Nov. 9, 1999 and assigned to the Assignee of the present invention, discloses an electromechanical pedal adjustment system. The system utilizes two linear motion safety switches each adapted to be mechanically connected between one of the pedals and a yoke that is pivotally connected to the pedal. Each of the switches are operable through linear movement created by movement of the pedal with respect to the yoke. Each switch includes linearly moveable contactors and associated contacts that are spaced apart along the length of the switch travel. The contactors and the contacts are part of an energizing circuit for the pedal adjusting motor that is only operable when the pedals are adjusted to the same, or nearly the same height. Thus, if a fault develops in the switches or an electrical circuit, the circuit is de-energized so that the motor will not operate until the system is repaired. While this type of system prevents substantial misalignment of the pedals, it does not provide for determination of absolute positioning of the pedals.
Another presently known system utilizes a potentiometer (often referred to as a xe2x80x9cpotxe2x80x9d) to monitor the height of the pedals. In this type of system, a pot is operatively connected to each pedal to create an output voltage that is proportional to the position of the pedal. The pot is mechanically coupled to an armature of a pedal adjustment motor by means of a large ratio gear train. The gear train reduces the number of revolutions the motor will normally rotate during complete travel of the pedals within their range of movement (typically several hundred revolutions) to less than one revolution. Thus, complete travel of the pedal from one end of its moveable range to the other corresponds to less than one revolution of the pot. When the pedal is adjusted via the motor, the motor also causes rotation of the contactor of the pot, thereby creating a variable voltage signal. The output voltages of each of the pots are compared by electronic circuitry to determine the difference between the output voltages. If the voltage difference exceeds a predetermined level corresponding to a fault condition, the motor is de-energized so that no further adjustment of the pedals is possible until the fault condition is addressed and/or repaired by a technician.
A significant disadvantage of this system is that failure of any of the mechanical linkage components between the motor and the pedal, such as the flexible drive cable, worm gears, pinions, drive clevis, etc., cannot be detected. This is because the pot is coupled to the motor. If the cable were to break and render one of the pedals adjustably inoperable, the pot would still generate a variable voltage signal. Thus, the motor could still be commanded to adjust the functioning pedal and the fault in the system would remain undetected.
Another disadvantage of this particular system is the complexity and relative high cost to manufacture and assemble the gear train requiring the large gear reduction.
Yet another disadvantage of this particular system is that it does not have an environmental seal adequate for most automotive applications. Exposure to various environmental conditions can cause failure of one or more electrical elements of the system and possibly create an intermittent or open electrical circuit. For example, during typical winter conditions when salt is utilized to melt ice and snow on the roads, salt water vapor may enter the electrical contact region of the pot and cause corrosion of the contacts. As an additional example, if the vehicle is used in dusty or dirty conditions, such as those found on a construction site or in the desert, airborne particulate matter may enter the pot and cause malfunction of the system.
The present invention solves all of the aforementioned problems and provides a robust design for a sensor of a vehicle pedal adjustment system.
The present invention provides a sensor for an adjustable system of a vehicle. The sensor is utilized to facilitate monitoring of adjustment positions with respect to a reference in the system. The sensor comprises a mechanical interface that allows for the input of movement and an electrical device coupled to the mechanical interface that is capable of changing an electrical signal in relation to the movement of the mechanical interface. The electrical signal, which is proportional to the movement input to the mechanical interface, is utilized by a control unit for control purposes, such as to control the positioning of vehicle control pedals, control the positioning of an adjustable seat of a vehicle, or to control the temperature adjustment in a vehicle HVAC system.
In a specific embodiment, the sensor includes a mechanical interface in communication with a pedal of an adjustable vehicle pedal assembly such that positional adjustment of the pedal imparts linear motion to the mechanical interface. The mechanical interface includes a mechanism that provides rotational motion from the imparted linear motion. An electrical device coupled to the mechanical interface is capable of changing an electrical signal in relation to the rotational movement provided by the mechanism of the mechanical interface. The rotational movement allows for a more effective sealing arrangement to protect the electrical device from adverse environmental conditions, especially in automotive applications.
In another embodiment, the sensor includes a mechanical interface including a shaft having a bearing surface and a carriage having a bearing surface that mates with the bearing surface of the shaft. The carriage is coupled to a portion of the pedal assembly to allow linear movement in response to position adjustment of the pedal. Thus, the linear movement of the carriage causes rotational movement of the shaft, which is coupled to an electrical device that is capable of changing an electrical signal associated with a control unit in relation to the rotational movement of the shaft.
The present invention also includes an adjustable pedal system for a vehicle having at least two vehicle control pedals. The system of the present invention comprises a motorized adjustment mechanism coupled to each pedal that effectuates movement of the pedal to an adjusted position, an electrical device coupled to each pedal and associated with an electrical circuit, and a control module in communication with the electrical circuit. The electrical device is capable of changing an electrical signal of the electrical circuit in relation to the adjusted position of the pedal and the control module controls the adjustment mechanism based on the electrical signal of the electrical circuit.
The present invention sensor can also be utilized in an adjustable seat system for a vehicle, wherein a sensor is coupled to a moveable member within the adjustment assembly associated with each axis of movement. The sensors provide a variable electrical signal that corresponds to positioning for each axis. The variable electrical signals are then utilized by a control unit to control the positioning of the seat.
The present invention sensor can also be utilized as a adjustable control in an instrument panel that requires a linear motion input by an operator of a vehicle. In a specific application, the sensor can be utilized in a vehicle HVAC system as an adjustable temperature control, wherein an operator can slide the mechanical interface to adjust the temperature output of the heating system of the automobile. The sliding of the mechanical interface would effectuate application of motion to the electrical device of the sensor to provide a variable electrical signal, which can then be used to provide variable temperature control to the system.
These and other aspects of the present invention will become apparent after consideration of the specification and the accompanying drawings.